The present invention relates to an apparatus and methods for mounting electronic components on a substrate.
Apparatuses for mounting electronic components, such as semiconductor chips onto a substrate, have electronic-component supplying sections where a number of parts feeders supplying electronic components are provided. In many cases, the electronic-component supplying sections are provided not only one side but both sides of the holding section of the substrate which is to be loaded with the electronic components, in order to accommodate the number of kinds of the electronic components to be mounted on the substrate. Another reason for the electronic-component supplying sections to be provided on both sides of the substrate holding section is to store the largest possible number of electronic components.
In the process of mounting the electronic component, in general, the positioning of the electronic component is corrected by capturing an image of the electronic components being held by a mounting head and by recognizing that image. The purpose of the foregoing process is to improve the positioning accuracy upon mounting the electronic component onto the substrate. To carry out the image recognition, the electronic component mounting apparatus is provided with a recognition section which captures and recognizes an image of the electronic component.
It is useful to have the image recognition section disposed adjacent to the route of the mounting head holding the electronic component, from the supplying sections to the substrate. Therefore, it is desirable for the image recognition sections to be disposed on both sides of the substrate holding section, when the supplying sections are provided, as is the foregoing case, on both sides of the substrate holding section. However, the image recognition section contains expensive devices. In many cases, therefore, only one image recognition section is provided to one side of the substrate holding section, to avoid increased cost of the apparatus.
As a result, the routes of the mounting head differ significantly depending on whether the electronic component is picked up from the supplying section provided with the image recognition section or from the other supplying section. In other words, when the mounting head picks up the electronic component from the supplying section without the image recognition section and mounts it onto the substrate, the mounting head, after picking up the electronic component, has to pass over the substrate to the image recognition section and then move back above the substrate. Therefore, otherwise unnecessary, extra movement is required, resulting in a longer carriage time and cycle time, and in turn, hindering an improvement in productivity.
The present invention aims at providing electronic component mounting methods which improve the productivity by reducing the cycle time.
An electronic component mounting method of the present invention includes the steps of; a) picking up an electronic component by a mounting head from a first supplying section and a second supplying section, each having a number of parts feeders, disposed on both sides of the substrate holding section for holding a substrate, b) recognizing the electronic component by a recognition section provided between the substrate holding section and the first supplying section, and c) moving and mounting the electronic component on the substrate held in the substrate holding section, wherein, the same kind of electronic components used in large numbers are stored in both of the first supplying section and the second supplying section.
An electronic component mounting apparatus of the present invention comprises following elements: a) a substrate holding section for holding a substrate; b) a first supplying section and a second supplying section, each having a number of parts feeders, disposed on both sides of the substrate holding section, each of the first supplying section and the second supplying section comprising; i) a table on which the parts feeders are disposed, ii) means for moving the table up and down, and iii) position determining means for determining the height direction position of the parts feeders when the table ascends, c) a mounting head for picking up an electronic component from the first and the second supplying sections; and d) a recognition section for recognizing the electronic component being held by the mounting head.
According to the present invention, the same kind of electronic components used in large numbers, is stored in both the first supplying section disposed adjacent to the recognition section on one side of the substrate holding section and the second supplying section disposed on the other side of the substrate holding section without the recognition section. The electronic components are picked up from the first supplying section in the normal operating conditions. The electronic components are picked up from the second supplying section only when the electronic components stored in the first supplying section run out. Thereby, the carriage distance in the normal operating conditions becomes shorter, reducing the cycle time.